Got a new 16' Z spar boom for my boat through Mack Sails. Was surprised at how cheap it was. Boom came set up for three internal reefing lines which made running the lines back to the cockpit way easier. Would caution you on cutting down the size of the main. The weather helm on a Westsail is mainly hull generated. Westsails aren't noted for their light air performance and any decrease in sail area would hurt . That and Westsails are at their best on a reach where mainsails are most effective. If you need to ease the weather helm, set your boat up so it is easy to reef and do it earlier. Have 5 figure miles sailing on a Westsail, btw.